Multiprotocol label, switching (MPLS) networks are widely deployed in service provider networks. Current MPLS networks are difficult to operate and maintain due to their use of label distribution protocol (LDP) and resource reservation protocol (RSVP)-traffic engineering (TE) (RSVP-TE) MPLS signaling protocols. In addition, each network device in an MPLS network needs to maintain a large amount of states for established label switched paths (LSPs). Further, new services may not be easily added to existing MPLS networks.
Software defined networking (SDN) is a networking architecture that decouples the control plane from the data plane. That decoupling allows for centralization of network control, enabling effective policy administration and flexible management. The centralization of network control facilitates various network functionalities such as network measurements, traffic engineering, enhanced quality of services, and enhanced access control. In addition, new services may be easily added to SDN-based networks. Thus, service providers may benefit from the SDN architecture.
An example SDN network is an OpenFlow network. OpenFlow provides a common communication protocol between SDN controllers and network nodes. The OpenFlow protocol describes messages exchanged between an OpenFlow controller and OpenFlow switches, where the OpenFlow controller programs the OpenFlow switches with flow forwarding entries for data forwarding.